Pickering emulsions stabilized by protein/polysaccharide polyelectrolyte complexes for lipase catalysis

Area of Science:

• Biocatalysis
• Colloid and Surface Science

Background:

• Pickering emulsions offer unique interfacial properties for catalysis.
• Protein/polysaccharide complexes present novel stabilization strategies.
• Biphasic catalysis requires efficient enzyme-stabilizer interactions at interfaces.

Purpose of the Study:

• To investigate the feasibility of ovalbumin/pectin stabilized Pickering emulsions for biphasic catalysis.
• To analyze the adsorption behavior of porcine pancreatic lipase (PPL) at the emulsion interface.
• To determine optimal conditions for p-NPP hydrolysis using this system.

Main Methods:

• Preparation and characterization of Pickering emulsions stabilized by ovalbumin/pectin polyelectrolyte complexes.
• Confocal laser scanning microscopy (CLSM) and Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) to study PPL adsorption.
• Enzymatic hydrolysis assays of p-nitrophenyl phosphate (p-NPP) under varying conditions.

Main Results:

• Porcine pancreatic lipase (PPL) adsorbed discretely to the emulsion interface despite shared negative charges.
• Hydrolysis of p-NPP was optimal at pH 6.5, with specific ratios and concentrations of stabilizer and enzyme.
• Under optimal conditions, the Pickering emulsion system yielded lower conversion rates and product yields compared to a conventional oil/water system.

Conclusions:

• Pickering emulsions stabilized by ovalbumin/pectin polyelectrolyte complexes may not be ideal for biphasic catalysis.
• The viscoelastic nature of the complexes potentially hindering optimal enzyme accessibility at the interface is a likely cause.
• Further research into interface properties and stabilizer design is warranted for improved biphasic catalytic systems.